Memory - Key studies.

Memory - Key studies.

1. Baddley

   • Short term memory study - Encoding
     • Participants were divided into 4 groups. Each group HEARD a list of 5 words from one of the categories.
       • Acoustically similar words (man, map, mad)
       • Acoustically Dissimilar words (pen, day, few)
       • Semantically similar words (great, big, large)
       • Semantically dissimilar words (hot, old, late)
     • Acoustically similar words are harder to recall (55% accurate)
     • STM relies on the sounds rather than meanings as shown with the difficulty found with similar words.
     • Evaluations
       • Supported by Conrad's study.
       • It shows a casual link between STM and recall accuracy
       • Might not reflect the complexity of encoding (simplex)
   • Long term memory - Encoding
     • The 4 groups were SHOWN a list of words, with the same procedure.
     • After 20 minutes, p.ps were given another task, then asked to recall in correct order.
     • Worse for semantically similar words (59% accuracy) Semantically dissimilar words (85%)
       • Recall was the same for acoustically similar and dissimilar words.
     • LTM primarily uses semantic coding.
     • Evaluations
       • There is a link between LTM and accuracy of recall.
       • Only LTM for words was tested past events may use a different type of encodement, (cannot be generalisied to all memory recall)

2. Jacobs

   • Short term memory - Capacity
     • Participants were read lists of either words or numbers to recall immediately after the presentation.
     • Gradually increasing the length of the digits until the p.ps could only recall accurately 50% of the time (in the correct order).
     • The results showed a difference between the ability to recall numbers and letters.. On average 9 numbers were recalled, and only 7 letters.
     • STM has a capacity of between 5 and 9 items. As age increases, they have better strategies for recall.
     • Evaluations
       • In 1887, the method would have been less rigorous, cofounding variables may have been possible.
       • Miller's findings support this study.
       • No consistency across different stimulus material.

3. Peterson

   • Short term memory - Duration
     • Participants were shown a consantant trigram (harder than vowels)
       • They put 3 constantans in a triangle because they are seen as less meaningful
     • They were asked to count number backwards, (as a distraction tasks making them stop rehearsing the trigrams.)
       • They were asked to recall the information after 3-18 seconds. They did this several times with different trigrams.
     • 80% recall after the first 3 seconds, only 10% could recall after 18 seconds rests. Time increased --> Less trigrams recalled by participants.
     • Evaluations
       • Not ecologically valid as it is not a normal everyday thing to recall letters.
       • Interference from previous trigrams caused poor recall?
       • Shows the effect of time on memory recall.

4. Bahrick

   • Very long term memory - Duration
     • 392 participants were shown photos from THEIR high school yearbook
     • There was two groups (recall and recognition)
       • Recognition group - Have photos and a list of names they had to match up.
         • Recognition group results : 90% after 14 years after graduation, 80% after 25 years, 75% after 34 years & 60% after 47 years.
         • Recognition tests shown LTM to be better than recall tests.
       • Recall group - Had photos without the names, they had to give names to.
         • Recall group results ; 60% after 7 years, less than 20% after 47 years.
     • Evalutations
       • Questionable as to if it shows duration or memory of age.
       • They may still be in touch with people from high school, and in the 70's people tended to stay in their hometowns = may have seen them recently.
       • It is all information that is relevant to them --> therefore they should remember it.
     • People can remember certain types of information.